Mardu Energy floods the board with small threats and uses Goblin Bombardment to convert them into reach, so your priority is stabilizing early and then burying them in Rhino tokens. Brotherhood's End is the premier sideboard card here, sweeping away Ragavan, Guide of Souls, Ocelot Pride, and Voice of Victory in one sorcery while leaving your bigger threats intact. Blood Moon is a powerful lock piece given their heavy reliance on nonbasics (Dalkovan Encampment, Elegant Parlor, Raucous Theater, shocks, fetches), while your own deck retains its core colored mana through basic Forest, Island, and Mountain. Inevitable Betrayal cascades off Shardless Agent or Violent Outburst and can steal Sephiroth, Fabled SOLDIER or Ragavan, turning their best threat against them. Wistfulness and Sink into Stupor are trimmed because slow card advantage and bounce spells are poor tempo plays against an aggressive board presence that will kill you before they shine.